Control mechanism for concrete mixers



May l, l945- A. MCMILLAN l 2,375,014

CONTROL MECHANISM FOR CONCRETE MIXERS May 1,'1945. A, MGMILLAN l 2,375,014

CONTROL MECHANISM FOR CONCRETE MIXERS Filed Feb. 15, 1944 2 sheets-sheet 2 Patented May 1, 1945 UNITED STATES PATENT- OFFICE H contraen rmoiizgroa concentra l f Andrew McMillan, Milwaukee, wis., `assigner to Chain Belt` Company, Milwaukee Wis., a cole-fA poration of Wisconsin pplcation February 1,5, 19411,- `Serial No. 522,479 y `V i solaires.` (01.-'14-53) l The invention relatesito 'concrete mixers and has lfor one` of its objectsthe-provsion of an improved mechanismV `for controlling certain of" the instrumentalities thereof. Forpurposes-oi`V dsclosureit will be `herendescribed as applied to control of the discharge chute of a concrete 4mixer of the socalled paving typeJ l Such: machines commonly include a rotatable mixing drum having an opening `in one endwall through ,which the mixed concrete is discharged at the conclusion `of the mixing cycle,` such dis-` charge being effected through4 movement of a discharge chute from a, normally `inoperative position., to one in which `it intercepts or receives the mixture being` agitated within the drum, and

conveys it through the said drum opening. `The movements of the chute to and from discharging position may be elected manually, but "more frequently the chutes .are linoved by power derived from the power plant ofthe: mixer; through mechu anism such, for example, ,as that disclosed `in U; S. Patent No.` `1,415,411;,granted May 9, 1922, on, an application filed by Samuel Shafer, Jr.

`In `the application heredisclosed,` the present invention is illustrated` as controllingone of these power` discharge mechanisms, and the control, While manually actuated `by the operatonwith `a minimum of eflort,actnallyeiects setting offthe` power discharge device into operation by means of power derived from the mixerpower plant. Since operation of Vthe "discharge chute is but one of several duties of the operator, and since under present] day practice `it must be performed `each 40 to'iO seconds, the fingertip controlthus provided results lin an `appreciable reduction in the i physical effort required and thereby lessens ifatiene of theop'erator. v

yItis also 1common `practice `to "provide mixers Y of the'paving as `well as ofyother well known types with timing devices, known `as batch meters. which are set into operation at the `beginn-ing of the mixing period and after a predeterminedtime give a `suitable signal orindication whereby the operator may knowthatfthe batch is completely .mixed and ready for discharge.l Frequentlyfinthe discharge chute will `have been moved'sufi ence characters desisnatelike parts views. andnwhmhl: c l p, l Eigurefris a,iragmentarysideelevationalview;` i

the power discharge device slightly in advance of the termination of thermixing period as `determined bythe batch meter, whereby lag between the completion of mixing and the `beginyning `of discharge of the mixed batch may be eliminated. `That is to say, ordinarilyitmay take an appreciable period of time for `the operator `to `react `at the end of the `mixing cycle and` put thepower discharge mechanism into operation n and thereafterseveral seconds to move the discharge chute from its, normal inoperative position-outside the drum to its dischargingposition within the drum,` and if the discharge mechanism is kept locked until the batch meter signals the i expiration of the vfull mixing period, yeven if the operator starts the power dischargev mechanism immediately `upon receiving the `batch `meter sig-` nal; several seconds `will necessarily elapse before ciently `teistert discharge, The present interlock is so arranged however, as `to unlock thepower discharge control adequately before thel batch metersignalso that bythe time such` `signal isy giventhe discharge chute ymay have at least pariially completed its movement from non-dischargingtodischarging position. l,

One form of apparatus constructed and ar.-

`ranged inaccordancewith the inventionds illustrated the. accompanying drawings forming a part ofytbis specialismen, in which like referin all the partly,broken` away and in section, illustratim;` suchifelements .of 'a well known example of a paving .mixeras are essential to an understand.` ing cflthe inventicm With power discharge ccntrol andinterloclring mechanism constructedwand arranged in accordanoe with the invention infccrpcrated therein;` l v Y. Fig; 2l is an enlarged,sectonalaelevational view,4

`taksen approximately on the plane indicated by l the :lille tml` of Eig. l, looking in thedirection of nism, which furthermoreis arranged to unlock 55 theearrows, showing the mechanism for eectins actuation of the startinglevernofa conventional pcwergdischanse `mechan-ism through power ie-` rivcdifrcm the :power plant of the mixer;` l i fiFig. ;3 is a sectional-,elevationalview of the pants lustratled inFg. 2, as seen fromthe left thereof; l l l l, is ptOP: plannview of the parts shown inFig-@'Zfld.` yn ,i

Fiss.. .z5 end i6, are views. larselv diaraccrnatic,` illustrating interlocking mechanism `between thebatchmeter andthe power discharse control mechanism, and showing various positions assumed by the parts in a cycle of operation.

Referring more particularly to Fig. 1, the conventional concrete mixer elements shown comprise a framework I mounted for ground traverse upon crawler treads II and having a mixing drum I2 -rotatably mounted within it upon rollers I3. Said drum is driven by a chain and sprocket drive I4 from a countershaft I5 which, during operation of the machine, is constantly driven from the power plant of the mixer (not shown). A discharge chute I6 is pivotally mounted on the framework I6, as at I1, and is adapted h the operator moves the control lever 41 from the to be swung from its inoperative position (shown- A in Fig. 1) through the discharge opening provided in the rear end wall I8 of the drum I2, to

a reversely inclined operative position, at leastv partially within said drum. This movement of' the chute, as well as reverse movement to with-` draw it from the drum at the completion of discharge,is accomplished through an arm 2l! carried by the shaft I1, a link 2I, a bell crank lever 22 and a link' 23 which is connected to the crank arm 24 of a power discharge device 25, which may be of the type disclosed in the above mentioned Shafer Patent No. 1,415,411. This device may be driven Afrom the countershaft I5 by a chain and sprocket drive 26, and is provided with a lever 21 by means of which it `mat7 be thrown into operation.

A batch meter 28 is also provided, for timing the mixing period and giving a signal at the conclusion thereof, usually an audible one by means of a bell 29.

The control mechanism of the present invention,l for actuating the starting lever 21 of the power discharge device 25, is best shown in Figs. 2, 3 and 4, and comprises a supporting bracket 30 mounted upon a member IU of the mixer framework. The said bracket-carries a bearing sleeve 3l in which is journalled'a rock shaft 32 provided at one end with a crank arm 33 carrying a. crank pin 34 upon which is journalled a lever 35 having arms 36 and 31 extending in opposite directions from the crank pin or .pivot 34. The lever arms 36 have a roller 38 journalled between their outer ends, and a cam or eccentric 39 is rigidly-mounted on the countershaft I5 in position to be engaged by the said roller. The lever arm 31 has an actuating rod 40 pivotally secured to it as at 4I, which rod extends downwardly and engages the slotted end of the starting lever 21 of the powery discharge mechanism 25.' A suitable spring 42, secured to the lever arm 31 and to thefframe member I0' or other appropriate fixed part ofthe apparatus may be employed to prevent disengagement of the rod 40 from the startinglever 21, and also to prevent unintentional engagement of the roller 38 with the constantly rotating cam or eccentric 39. A spring 21', secured to the starting lever 21 and to the frame member I0 or other appropriately lixed part ofthe apparatus, may be employed to keep the starting lever 21 in proper location to contact with the rod 40.

The shaft32 also carries an actuating arm 45 which is connected to an arm 46 (see Figs. 5 and 6) of a control lever 41 which is pivotally mounted as at 48 in a housing 49 located conveniently with respect to the operator's station, as for example, on the drum shielding or protecting panel 50. The connections between the arms i5 and 4S preferably comprise a well known form of` exible cable, wherein a wire or'strand 5I is surrounded by and longitudinally slidable full line position shown in Fig. 5 to the broken line position indicated therein, which swings the arm 46 upwardly thereby drawing the wire 5I through its sheath or covering 52 and pulling the arm 45 of shaft 32 downwardly. The said shaft is thus partially rotated to swing its crank arm 33, the crank pin 34 and the lever 35 to the broken line position indicated in said Fig. 5, whereby the follower roller 38 is moved to a position to be engaged by the cam or eccentric 39. The countershaft I5 which carries this cam is being constantly rotated at a relatively low speed-say to 10D-R. P. M.-and the cam will thus act upon the roller 38 to swing the lever 35 on its pivot 34, raising its arms 36 and depressing its arm 31. This movement, through the rod 40, will depress the starting lever 21 of the power discharge mechanism 25, as shown in Fig. 6, setting it into operation; and through its linkage 24, 23, 22, 2l and 20, the said mechanism will move the chute I6 into its discharge position within the drum in the usual manner. Since the cycle of operation of the mechainsm 25 includes automatic stopping of the said mechanism and, resetting of its starting lever 21 when the chute reaches its discharge position in the drum, the operator may restore the control lever 41 to its normal full line position as soon as inward movement of the discharge chute has begun. This return of the control lever to normal will of course restore the parts 32, 33, 34, 35, 38 and 45 to normal, with the roller 38 out of range of the constantly rotating eccentric 39. When discharge has been completed, the operator again manipulates the control lever 41 to cause the actuating mechanism 32, 33, 35, 33, 39, 40 to again depress the starting lever 21 whereupon the power discharge device 25 will return the chute to its inoperatvie position'of Fig. 1, and then stop and reset its lever 21. Crank arm 33 is of such length as to have the same placed at substantially 90 degrees to lever 36 when the operator moves control lever 41 to the broken line position as shown in Fig. 5 so that the reacting force from starting the power discharge may be transmitted to bearing sleeve 3|, rather than to the operator through lever 41, which would happen should the crank arm be of greater length.

The interlock between the batch meter Land control mechanism, referred to above, is indicated in Fig. l, and shown more in detail, although rather diagrammatically, in Figs. 5 and 6. The batch meter 28 may be of any appropriate type, such for example as that disclosed in U. S. Patent 2,018,964 granted October 29, 1935, on an application filed by Rudolph F. Lindow. Brieily, such a batch meter is provided with a power-driven shaft which carries a control disk 6I having a recess 62 in its periphery. A dog 63 is carried by a control shaft 64 whichr also carries a starting lever 65, and the said dog is provided with a toe 66 which is vheld engaged in the notch 62 by spring63' when the meter is annoia! stopped ing; si, fand-which Tides Lupen" the 1 periphery of the disk" 61" when *the meter is `tim` ing `an operation (Flieg-in" The vlength ottime requiredfior 'disc Blfto make one revolution determines -t-he mixing andthe -`speed 'at scribedin said-patentl"` 1 The-interlockmechanism comprises a cam disk `mountedfon`the` batch meter-shaft fill and lhaving a'iprojection Ni *fn bell crank lever' whichv disc tirevolvesis controlled by-means de- 12 is"`pivoted asiatA lfand one ofi-ts arms `*M- choredthereat, as indicated at 88, so that lthe i enii`18 of the vv-irait' maybe-projected into and withdrawn 'from thefpath of the-arm Mi 'of thefcontrol lever." `The sheath 119 'is secured by acl'ip 82 to an arm B3 vcarried bythe batch meter dog 6'3, and may `nirthermore be anchored as 4ati to' frame ILI adjacent the `batch meter.- i i U The full line positions shown inFig. 5 .are those whichthe respective parts occupy .say 4iii/.e secends before the end of the batch meter cycle, itbeing noted that the end 118 of the-wire 118 overlies 'the end ci the l control .ieverwarmwld thereby locking the said lever against operation to initiate movement .of theclmte I8 todischarging position. Continued rotation or the batch meter :shaft 'lill` :and its 'ldislcs'l and 10 brin-gs these parts to the `broken line .positionsindicated 5 lsay a iewllseconds before the batch meter stops, whereby.' the ycam projection 11| on disk 10 will have rocked the bell crank leverI'l-Z in a counterclockwise direction, pulling the wire aga-m manipuiatedfat @inclusion of medisch-aree `toset the power Idischarge device 25 into operaL tionagain to withdraw the chuterirom the drum, i

as above explained.` v.

*The 'interlockfwill again become effective only whenfthe-batch meter "28 is re-started to time a i new mixinglperiod That is to say, when the batch meter starting lever 65'is moved counter; clockwise to lift the toe GE'of the dog 63 .out of the recessiof the-locking disk lfthe said dog with its' jarm 83 will be swung back to the broken lineposition of Fig. 6. 'I'he effect of. this will be `tolstraigl'i-ten out thesag orbuckle .in the cable 18,19 between the clips 8| and f82\,.as indicatedin broken lines infFig. o, and A.since the end of `the Wire '18 which is `attached `to the arm` 18 of lever 12 can not move, relative move.` mentbetween the fwire and `lts sheath 19 will occur in that portion of the cable `between lthe anchors 81 and@ with the result that the end ll'o thewire will; again be :projected .into .the

path :oithearm 46 of the control lever, .as also indicated in broken linesinFig. 16. The .control lever "thus `will beagain locked against` lma-A nipuflation until thepartsagain reach the lirr.l

rfpositions, when the operations above described willbe repeated? f i 1 i. ;v i While one form .of` the. invention has been il. lustrated and described, it will be readily under,-V stood-Athat `those .skilled in the art may `vary the details of construction as Well as the precise a1*- rangeme'nt ot parts; without ndeparting from the spirit of theinvention, andtherefore itis not wished "to belimited tothe above :disclosure ex ceptas may be `required by the claims.

What i-s claimed is: i y l. In .actuating` mechanism for a concrete mixer lr-istrumentaliiy,` a power driven cam; a rookshaft mounted `adjacent said-cam, provided vvlitlii-a crank arimzj i -a f lever` pivotally 1 mounted on `said crank arm, having a f-oll-Lowerfor engagement with saidrcam' `connections betweensaid lever and `the 'instrumenrtality, to' be` controllod;` land manually operableemeans `for rocking said shaft 4 be engaged by the cam.

power discharge mechanism 25 as above de-v scribed, and thechute I6 thus may be moved at least partially to its discharging position by the time the batch meter reaches the end of its cycle andstops. i

The parts Will now be in the positions indicated in lfull lines .in Fig. 6. Spring 83 will have caused the toe 66 of the dog G3 to enter the notch 62 of the batch meter control disk El, thereby locking the batch meter against further operation until the said toe is withdrawn from the notch through actuation of the starting lever 65 to begin a new cycle. The cam projection 1l will have moved from beneath the roller 15, permitting spring 12' to return the bell crank lever 12 to its original position. This return movement of lever 12 will push upon the wire 18, but since this movement is coincident with and in the same direction as the movement of the dog 63 `to locking position, and since the cable sheath 19 is anchored to the arm 83 of the said dog, there will b e-no relative I movement of the wire within the sheath, but in- Mechanism for governingactuation of acontrol element of a concrete mixer during the timing of a function of the machine: said mechanism comprising a device for timing said functon;` means engageable with said control element at the beginning of a cycle of said timing device, whereby to prevent actuation of said element; and means operable by the timing device at; a, predetermined interval priorto the completion of its timing cycle, to disengage the lrst named means from the control element, whereby the latter may then bel actuated.

3. Mechanism for governing actuation of a movable control element of a concrete mixer during a mixing `period ofthe machine: said mech anism comprising adevice for timing said mixing period; a member movable into and out of the path of said control element; means for moving said member into the pathA of the control element.

simultaneously with the initiation of `a timing cycle of said device, whereby actuation of the element may be prevented; and means operable by the timing device to withdraw the member from the path of the control elementV at a predetermined interval prior to the completion of the timing cycle.

4. Mechanism for governing actuation of`a movable control element of a concrete mixer during a mixing period of the machine; said mechanism comprising a device for timing said mixing period, said device having a starting lever; a member movable to engage and disengage said control element; connections between said member and starting lever whereby the member may be moved to engage the control element simultaneously with the beginning of a timing cycle of the timing device and thus prevent actuation of the control element; and means operable by the timing device just prior to the completion of its cycle to disengage the member from the control element, whereby the latter may then be actuated.

5. Mechanism for governing actuation of a movable control element of a concrete mixer during a mixing period of the machine; said mechanism comprising a device for timing said mixing period, said device having a starting lever; a member movable to engage and disengage said control element; lost motion connections between said member and starting lever whereby the member may be moved to engage the control element simultaneously with the initiation of a cycle of the timing device and thus prevent actuation of the control element; and cam controlled means operable by the timing device at apredetermined interval prior to the completion of its cycle to disengage the member from the control element, whereby to permit actuation of the latter.

6. Mechanism for governing actuation of a movable control element of a concrete mixer during the timing of a function of the machine: said mechanism comprising a device for timing said function, said device having means for starting it into operation; a flexible cable member extending from the timing device and having a portion projectible into a position to be engaged by the control element whereby to prevent actuation of the latter; connections between said cable and the starting means of the timing device whereby the cable member may be projected into said element-engaging position. simultaneously with the initiation of a cycle of the timing device;

and means operable by said device for withdrawing the cable member from said element-engaging position toward the end of the timing cycle.

7. Mechanism for governing,r actuation of a movable control element of a concrete mixer during the timing of a function of the machine: said mechanism comprising a device for timing said function, said device having means for starting it into operation; a flexible cable member extending from the timing device and having a portion movable into engagement with the control element to prevent actuation of the latter; lost motion connections between said cable member and the starting means of the timing device whereby the member may be moved to engage the control element at the beginning of a cycle of the timing device; and cam actuated means connected to the cable member and operable by the timing device at a predetermined interval prior to the end of its timing cycle to withdraw the cable member from engagement with the control element.

8. Mechanism for governing actuation of a movable control element of a concrete mixer during the timing of a function of the machine: said mechanism comprising a device for timing said function, said device being provided with means for starting it into operation; a flexible cable member extending from the timing device and having a portion projectible into the path of said control element whereby to prevent actuation of the latter; a sheath enclosing and slidably accommodating said cable member, a portion of said sheath spaced from the timing device being anchored against movement; connections between the sheath and starting means of the timing jdevice whereby the cable member may be moved into the path of the control element at the beginning of a cycle of the timing device; and means connected to the cable member and operable by the timing device at a predetermined interval prior to the completion of its cycle to withdraw the cable member from the path of the control element.

ANDREW MCMILLAN. 

